The present invention is primarily directed to the precise measurement of down hole variables in oil wells.
It has been for many years the custom to make a temperature run in a production or injection well as a routine part of a production logging operation. The data so gathered is recorded on an analog roll chart in the logging truck. Although there are many exceptions for varying reasons, the typical format is to roll the chart paper in synchronization with the cable odometer so that two inches of chart travel is equal to 100 feet of depth. The chart paper is usually ten inches wide excluding the perforated margin. This across-chart axis is used for the amplitude of the variable being measured.